Other users cannot connect to Linux in single-user mode.

One premise of using the single-user mode is that your system Boot Tool (grub) works normally. Otherwise, you must use the repair mode for system maintenance.

Note: In single-user mode, network service is not enabled and remote connection is not supported.

Different Run levels in the centos system indicate different running states of the system. For example, if the Linux server is in the running level 3 during normal running, it is a multi-user mode that can provide network services; the running level 1 only allows administrators to operate on the server host through a single console, that is, "single user mode ".

Take centos as an example:

The centos system enters the single-user mode.

The premise of entering the single-user mode is that the centos System Boot Tool works properly.

The following uses GRUB as an example to describe the access method.

I. Power up. When the following interface is started, Press ESC:

Ii. Go to the following interface and press:

There are three operation buttons "A", "E", and "C" in the grub boot menu. You can use these buttons to enter the single-user mode.

1. Use the "A" operation button to enter the single-user mode-recommended: simple operation (I did not test the cup.)

This is the fastest way for centos to enter the single-user mode.

Use the "A" operation button in the grub Startup menu to edit the Kernel Parameter and enter single at the end of the line to inform the Linux kernel that the subsequent startup process needs to enter the single user mode. Press enter.

After entering the single-user mode

When the centos system enters the single-user mode, you do not need to enter the user name and password. After the centos system is started, the administrator root permission is directly obtained. The console prompt is "#".

2nd methods:

1. Press E above, which means "Edit command line" before the boot, enter the following interface, move the cursor to line 2nd with the up/down key (the line starting with the kernel)

2. move the cursor over this line, press the e key to edit this line, and then enterLinux singleNote that two spaces are similar to the following:
Kernel/boot/vmlinuz-2.6.11-1.1369_FC4 Ro root = label =/1Rhgb quiet Linux single

Input:LinuxNote that there is a space before and after Linux. Before entering single, the following interface is displayed:

Enter single and press Enter.

Go to the following page (in this case, 2nd rows are guided by a single user), and press B to guide.

At this time, no other user can connect to the system. After you finish the task, reboot will start the mode specified in/etc/inittab, such as 3 (multiple users ).